Intranasal oxytocin administration prior to exposure therapy for arachnophobia impedes treatment response.

Abstract

Recent years have seen the emergence of a new paradigm for treatment of anxiety disorders focusing on development of drugs that facilitate psychotherapies via targeted effects on neuroplasticity. One compound that has generated interest in this regard is oxytocin (OT), a mammalian neuropeptide that modulates activity of the neurocircuit mediating fear extinction and memory processes. Recent research in healthy humans has suggested that intranasal OT administered prior to fear extinction training enhances fear extinction performance, supporting its potential to augment exposure-based psychotherapy. Here, we tested the hypothesis that OT treatment would facilitate response to exposure therapy in patients with specific phobia. We conducted a small proof-of-concept trial investigating the effect of pretreatment intranasal OT administration on a brief, single-session exposure treatment for arachnophobia (fear of spiders). The study was randomized, double-blind, and placebo controlled (n = 13 placebo, 11 females; n = 10 OT, 8 females) with 1-week and 1-month follow-up assessments. Dependent measures attended to arachnophobia symptoms (self-report), phobic behavior (behavioral avoidance of spider task), and treatment credibility/therapeutic alliance. Administration of OT prior to exposure therapy tended to impede treatment response as measured by self-report of symptoms at both follow-up periods. OT treatment did not significantly affect behavioral measures of fear. Immediately after OT administration but before therapy, the OT group trended toward less confidence in the treatment. The OT group also trended toward lower ratings of therapeutic alliance than placebo. These results suggest that OT administration effects on extinction may vary depending on conditions and population.